?-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis.

Saunders, Bryan; Elliott-Sale, Kirsty; Artioli, Guilherme G.; Swinton, Paul A.; Dolan, Eimear; Roschel, Hamilton; Sale, Craig; Gualano, Bruno

Abstract

Objective To conduct a systematic review and meta-Analysis of the evidence on the effects of β-Alanine supplementation on exercise capacity and performance. Design This study was designed in accordance with PRISMA guidelines. A 3-level mixed effects model was employed to model effect sizes and account for dependencies within data. Data sources 3 databases (PubMed, Google Scholar, Web of Science) were searched using a number of terms (b € β-Alanine' and b € Beta-Alanine' combined with b € supplementation', b € exercise', b € training', b € athlete', b € performance' and b € carnosine'). Eligibility criteria for selecting studies Inclusion/exclusion criteria limited articles to double-blinded, placebo-controlled studies investigating the effects of β-Alanine supplementation on an exercise measure. All healthy participant populations were considered, while supplementation protocols were restricted to chronic ingestion. Cross-over designs were excluded due to the long washout period for skeletal muscle carnosine following supplementation. A single outcome measure was extracted for each exercise protocol and converted to effect sizes for meta-Analyses. Results 40 individual studies employing 65 different exercise protocols and totalling 70 exercise measures in 1461 participants were included in the analyses. A significant overall effect size of 0.18 (95% CI 0.08 to 0.28) was shown. Meta-regression demonstrated that exercise duration significantly (p=0.004) moderated effect sizes. Subgroup analyses also identified the type of exercise as a significant (p=0.013) moderator of effect sizes within an exercise time frame of 0.5-10b €.min with greater effect sizes for exercise capacity (0.4998 (95% CI 0.246 to 0.753)) versus performance (0.1078 (95% CI b '0.201 to 0.416)). There was no moderating effect of training status (p=0.559), intermittent or continuous exercise (p=0.436) or total amount of β-Alanine ingested (p=0.438). Co-supplementation with sodium bicarbonate resulted in the largest effect size when compared with placebo (0.43 (95% CI 0.22 to 0.64)). Summary/conclusions β-Alanine had a significant overall effect while subgroup analyses revealed a number of modifying factors. These data allow individuals to make informed decisions as to the likelihood of an ergogenic effect with β-Alanine supplementation based on their chosen exercise modality.

Citation

SAUNDERS, B., ELLIOTT-SALE, K., ARTIOLI, G.G., SWINTON, P.A., DOLAN, E., ROSCHEL, H., SALE, C. and GUALANO, B. 2017. ß-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis. British journal of sports medicine [online], 51(8), pages 658-669. Available from: https://doi.org/10.1136/bjsports-2016-096396

• Journal Article Type: Review
• Acceptance Date: Sep 28, 2016
• Online Publication Date: Oct 18, 2016
• Publication Date: Apr 1, 2017
• Deposit Date: Oct 31, 2016
• Publicly Available Date: Oct 31, 2016
• Journal: British journal of sports medicine
• Print ISSN: 0306-3674
• Electronic ISSN: 1473-0480
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 51
• Issue: 8
• Pages: 658-669
• DOI: https://doi.org/10.1136/bjsports-2016-096396
• Keywords: Beta alanine supplementation; Muscle carnosine; Exercise capacity; Exercise performance; Acidosis; Buffering capacity; Sodium bicarbonate; Cosupplementation
• Public URL: http://hdl.handle.net/10059/1913